For production of semiconductor devices, a known technique is to use a mask in order to implant an impurity into a predetermined region of a semiconductor substrate (for instance, see Japanese Unexamined Patent Publication (Kokai) No. HEI-5-275637).
For production of semiconductor devices, a known technique is to amorphize some portions of a semiconductor substrate, implant an impurity into the amorphized portions, and then recrystallize the amorphized portions by heat treatment (for instance, see Japanese Unexamined Patent Publication (Kokai) No. 2005-268792).